Temperature Converter
Instantly convert temperature scales between Celsius, Fahrenheit, and Kelvin. Features exact affine thermodynamic formulas, support for negative values, and automatic validation at absolute zero.
°F = (°C × 9/5) + 32
Common Conversions
How Temperature Conversions Work
Unlike length or weight, temperature scales do not share a common zero point (except Kelvin and Rankine). They are affine transformations requiring both a scaling factor and an additive offset.
Celsius & Fahrenheit
A temperature change of 1 °C equals a change of 1.8 °F (9/5). The constant 32 accounts for the freezing point of water (0 °C = 32 °F).
Celsius & Kelvin
The Kelvin scale is an absolute thermodynamic scale where 1 K has the exact same unit size as 1 °C, but zero Kelvin corresponds to absolute zero.
Absolute Zero Physical Boundary
Absolute zero is the theoretical lowest temperature where all molecular motion ceases. By international thermodynamic definition, absolute zero occurs at:
EverydayNumbers automatically detects and rejects entries below these physical thresholds with an explanatory message, preventing unphysical thermodynamic outputs.
Key Temperature Benchmarks
| Physical Milestone | °C | °F | Kelvin (K) |
|---|---|---|---|
| Absolute Zero | -273.15 °C | -459.67 °F | 0 K |
| Freezing Point of Water | 0 °C | 32 °F | 273.15 K |
| Standard Room Temperature | 20 °C | 68 °F | 293.15 K |
| Human Body Temperature | 37 °C | 98.6 °F | 310.15 K |
| Boiling Point of Water (1 atm) | 100 °C | 212 °F | 373.15 K |
Common Worked Examples
Example 1: Convert 25 °C to Fahrenheit
(25 × 9/5) + 32 = 45 + 32 = 77 °F.
Example 2: Convert 98.6 °F to Celsius
(98.6 - 32) × 5/9 = 66.6 × 5/9 = 37 °C.